防波堤建設による環境変化と移植アマモ場の拡大

概要

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The objective of this study is to clarify the effect of wave control by the construction of breakwater and eelgrass transplantation on eelgrass bed formation. We investigated the changes in environmental factors after the construction of the breakwater and transplanted eelgrass bed at the coast of Shimokamagari Island in the Seto Inland Sea, Japan. The rafting reproductive shoots with seeds in natural beds were predicted to be transported by the current to the transplantation area before the construction of the breakwater. However, the eelgrass bed was not formed. Wave height at the transplantation area was predicted to decrease to less than 1/5 due to the construction of the breakwater. This value was the same as those obtained for natural beds. Sediment inside the breakwater was muddier than outside and had an optimum grain size for eelgrass. Sea bottom level was stable inside the breakwater, whereas scouring that uprooted eelgrass occurred outside the breakwater in winter. The transplanted bed inside the breakwater expanded from 2,000m2 to 4,200m2 in two years. The moderate reduction in wave height and sediment stability caused by the construction of the breakwater played an important role in eelgrass bed formation and eelgrass transplantation.
社団法人　日本水環境学会の論文
2003-12-10